About your problem:
Get a Morcas Dryad first. These tree charms are actually very kind and fun to be around with, they are just often misunderstood.. BUT they do have an evil look. Introduce this charm to your Necro collection will make the introduction of more tree charms a lot easier.
More important tho, is this: Tree charms are a lifestyle! The real question here is, are you willing to bring out the tree charms more often then these fake Necro charms? Or are you one of those "I own Tree charms just to own them, but I prefer to look like a way to small, not powerfull version of Necro while Im supossed to be a healer" type? If thats the case, dont bother, instead, collect all those less cool and more expensive charms
Your choice!